of chicago



- F. SPAULDING.

MOVING PICTURE PROJECTION MACHINE APPLICATION FILED MAY 5, 1919.

v Patented Nov. 11, 1919.

iIlIH' lllIIIllllllllihlllllllllllllllllllllllll Illlllllllllllll Illlll llllllllllH Irulev'm i I 21, alfixed to shaft 22 hearing feed sprocket.

- UNITED STATES PATENT OFFICE.

FRANKLIN SPAULDING, 'OF CHICAGO, ILLINOIS, ASSIGNOR 0F CHRISTOPHER, OF CHICAGO, ILLINOIS.

MOVING-PICTURE-PROJECTION MACHINE.

vision of an improved mechanism for ad-- vancing the film before the light aperture in a moving picture apparatus, by a step by step or intermittent motion. v y

In the accompanying drawings;

Figure 1 is a side View partly in section of a portion of a moving picture projection machine illustrating the application of my i' trated by Figs. 4 and 5. Fig. 2 is a detail view from the left of .Fig. 1, showing the ,cam disk, polygonal invention thereto;

gear, and feed sprocket, and v Figs. 3, 4 and 5 are detall sections on line w'w of Fig. 2, showing successive positions of the partsduring rotation of the cam disk.

In the embodiment of the; invention chosen for purposes of illustration, l0 designates the driving shaft. This shaft, by means of gears 11, drives spool-driving shaft 12, and

shutter 13' rotating before light aperture 14, in film gate 15.. Driving shaft 10' also drives shaft 16 through intermediary gears 17, 18. Shaft 16 carries a balance wheel, as 19, and a cam disk, as 20, both rigidly secured thereon. Cam disk 20 by causing rotation of gear 23, causes motion of the film 24, by engagement of the spurs 23 on the sprocket with the perforations in the margins of the film provided for the purpose.

The present invention lies in characteristics of the cam disk and cooperating gear and to the peculiar coaction between this mechanism and the film movement.

A large portion of the face of cam disk 20 is a plane surface, as illustrated in F 1g. 1 and while this portion of the disk is coacting with the gear, 'an edge of the gear lies closely adjacent and parallel thereto. this position the polygonal gear 21 is locked against movement. Cam disk 20 bears two cam surfaces each projecting from the 'sur: face of the disk. These cams aredesignated 25 and 26 in the drawing and are shown as Specification of Letters Patent. Application filed May 5, 1919. Serial no. 294,920.

form throughout the period.

light is passing through it sured. the peculiar instead of one of four sides,

Patented Nov. 11, 1919.

separated by a spiral ,groovev 27, which groove is provided to allow the angle between successive edges of the, gear to swing toward the disk. I

'Assuming the parts to be in the relative positions ofFigs. 1 and 2, if the cam disk,

be rotated in the direction indicated by the arrow of Fig. 2, cam surface 25. will first act upon gear 21, causing the initial movement as indicated in Fig. 3, by displacing an angle thereof to the right. In the position of the parts shown in the polygonal gear has just made its initial entrance into spiral groove. 27 Immediately after this initial movement of the polygonal gear cam surface 26 comes into action as indicated, pressing downward upon the next occurring edge of the gear and continuing its rotation, as successively illus- Cam surfaces 25 andf26 are so designed ONE-HALF TO GEORGE W.

Fig. 3 the angle 28 of that the initial movement of gear 21 and i 4 the final p rtion of'the movement caused by each actuation of the same by disk 20, are each much slower than is the motion thereof during the middle portion of its moving period. This peculiarity of movement very important in the'actuation of films since a smooth action of the film is thereby secured and it is possible to move the film much more rap dly during the middle portion of itsmovmg period'and to secure a higher average speed of movement than would be possible if the movement was uni- The locking of the gear against movement while, the plane portion of the cam disk is moving adjacent an edge of the gear is, also important,

since absence of movement of the filmwhile is thereby in- The action of cam surfaces 25 and 26 upon gearg2l is a wedging action, that a plane perpendicular to the cam disk passing through the axis of shaft 22 would out either of these cam surfaces in a line out of parallelwithsaid shaft. In order that the edges of the gear 21 may coact with the cam surfaces throughout their full thick- .ness these edges-are beveled as indicated in Fig. 2. The result is that the edges of the polygonal gear constitute a frustum of a pyramid, as illustrated.

'It will be evident that atriangular gear,

or a gear of which means more than four sides might be used. Howi able features which would otherwise be attendant upon a quick movement of the film are eliminated.

While the particular embodiment of the invention chosen for illustration is a motion picture projecting machine, it will be understood that the invention is equally applicable to motion picture cameras.

I claim-as my invention:

1. A moving picture apparatus comprising, a light aperture, a feed roller for intermittently moving a film in front of said aperture, a polygonal gearing for actuating said roller, and a cam disk turning on an axis at an angle to the axis of the roller lockin said earin ailainst movement during a portion of the rotation of the disk, said disk bearing two cams for operation on suc cessive edges of said gearinig for rotation thereof.

.2. A moving picture apparatus compris-' ing, a light aperture, a feed roller for intermittently moving a film in front of said aperture, a polygonal gearing for actuating said, roller, and a cam disk having a plane surface over a portion of its face turning closely adjacent an edge of said gear, a cam projecting from said surface adapted by contact with said gear, near an angle thereof to start movement of said gear slowly and a second cam adapted by contact with the succeeding angle of the gear to continue movement thereof rapidly whereby said film is intermittently fed past said aperture.

3. A moving picture apparatus comprising a feed roller, a shaft therefor, a polygonal gear on said shaft, a driving shaft arranged at right angles to said roller shaft, a cam disk on said driving shaft and having plane and cam surface portions, said plane surface portion moving in a plane parallel and closely adjacent to an edge of said polygonal gear, a cam projecting from said disk adapted to contact with said edge near an angle thereof to start rotation thereof slowly. a groove in said disk for passage of the succeeding angle and a second cam on said disk adapted to contact with the succeeding edge of said gear to continue rotation thereof more rapidly whereby said feed roller is given an intermittent motion, and is locked against movement between said motions.

l. In a motion picture apparatus. in combination, a pair of shafts at an angle to each other, means for driving one of said shafts, a cam disk on the driven shaft, said disk having a spiral groove flanked by projecting cam surfaces, a feed roller and a polygonal gear onthe other shaft, edges of said gear lying successively closely adjacent said disk, one of said cams adapted to contact with an edge of said gear and startmove ment thereof and the other cam surface adapted to contact with the succeeding edge and complete a partial rotation of said feed roller.

5. In a motion picture apparatus in combination, a driving and a driven shaft in perpendicular relation, means for operating the driving shaft, a cam disk on the driving shaft, a major portion of the face of the said disk being a plane surface, two projecting cam surfaces on the face of said disk separated by a spial groove, a gear on said driven shaft having four equal edges, the edges of said gear forming the frustum of a pyramid, said gear so placed that its successive edges lie closely adjacent the plane portion of said disk whereby the cam surfaces of said disk act successively on successive sides of angles of said gear to cause successive partial rotations thereof, the angles'of said gear projecting into the spiral groove during movements of the gear, and a feed roller on said gear shaft.

6. In a motion picture projection machine, in combination, two shafts in perpendicular relation, means for driving one of the shafts at constant speed, a disk mounted on the shaft thus driven, such disk having a flat radial surface and being channeled, the channel extending obliquely inward across the flat face of the disk from the periphery of the disk and the tongue thus formed be- .ing raised above the plane of the flat face of the disk at its free end. a polygonal wheel mounted on the othcr shaft, such wheel having straight peripheral edges which ride upon the said flat face of the disk in the path of the said channel. and a film feeding sprocket also mounted on the last mentioned shaft.

FRANKLIN SPAULDING. 

